This invention relates to the generation of audio signals during play of a software (e.g., motion picture) carrier, and more particularly to a technique by which multiple dialog languages may be recorded on separate audio tracks of the same carrier without requiring a full track for each language version.
The most widespread medium for distributing motion pictures is the videocassette. The conventional practice is to provide only one language soundtrack on each videocassette. This means that different versions of the same motion picture must be prepared for distribution in different countries. Rather than to dedicate a different version of the same motion picture to each of several different languages, it would be far more advantageous to provide all desired sound tracks, containing different dialog languages, on the same carrier; this would require the production of far fewer versions of the same motion picture. Because of the large storage requirements, however, this has not proven to be practical. In fact, the only practical consumer use of multiple sound tracks on the same carrier is the provision of annotated and non-annotated soundtracks in some laserdisc releases. (It is possible, for example, to store different soundtracks in the digital and analog audio channels of a laserdisc.)
Despite the fact that it has occurred to others in the prior art to provide multiple soundtracks on the same software carrier, certainly the provision of perhaps a dozen different soundtracks, in different dialog languages, all on the same consumer software carrier, is not to be found anywhere. Not only are there no consumer players capable of selecting one from among so many different soundtracks, but software publishers have just not found it practical to store so much audio information on a single carrier. The traditional approach is to publish different versions of the same motion picture for distribution in different territories where different languages are spoken.
Digitally encoded optical disks are in theory far superior for the distribution of motion pictures and other forms of presentation. Especially advantageous is the use of xe2x80x9ccompressed video,xe2x80x9d by which it is possible to digitally encode a motion picture on a disk no larger than the present-day audio CD. While much effort has been expended in developing compressed video systems, less work has been devoted to the provision of multiple soundtracks on the same software carrier. The conventional thinking is to pack as much video as possible on any given disk, but still to provide a different soundtrack version carrier for each required dialog language.
It is therefore an object of this invention to provide a system and method for a software publisher to record on a software carrier, such as an optical disk, a motion picture accompanied with multiple soundtracks, in different dialog languages, while at the same time eliminating redundant information so that the storage is as efficient as possible.
A key to the understanding of the present invention is that there are sections of many video programs in which no dialog occurs. In the absence of dialog, there is no reason to provide a language-specific track. During any xe2x80x9cno dialogxe2x80x9d sequence, all that are available, if even that, are music and effects. Thus a music and effects (MandE) track is really all that is necessaryxe2x80x94for all language versionsxe2x80x94during much of the total running time of a motion picture. In fact, an MandE track is all that is required in the usual case for far more than half the running time. Obviously, a Shakespearean movie will have more dialog, and hence more language-specific dialog, than an action-adventure movie. Nevertheless, most present-day releases have far more non-dialog MandE than they do the spoken word
Before summarizing the invention, it is to be appreciated that the present invention contemplates data-efficient storage and recovery of various audio versions, and not just different language movie soundtracks. For example. multiple soundtracks could include teaching and testing versions of the same material, and there could perhaps be teaching and testing versions for multiple levels of expertise. The multiple soundtracks that would be provided in such a case might even have some dialog in common, not only MandE. Thus, it is to be understood that the object of.the invention is to provide a plurality of audio tracks synchronized with a motion picture, and not necessarily audio tracks which differ only in terms of language. It is also to be understood that the invention is not limited to a particular medium, and it is applicable to tape carriers and all digital storage media, not just the optical disks of the illustrative embodiment of the invention. Nor is the invention limited only to the distribution of motion pictures. For example, in an extreme case, the invention is applicable to the distribution of a library of still pictures, in which case there is no xe2x80x9cmotionxe2x80x9d at all. The term xe2x80x9caudio tracksxe2x80x9d thus embraces much more than audio tracks with different dialog languages, the term xe2x80x9csoftware publisherxe2x80x9d thus embraces much more than a motion picture company, and the term xe2x80x9ccarrierxe2x80x9d embraces much more than a digitally encoded optical disk.
The illustrative embodiment of the invention is an optical disk which includes multiple audio tracks synchronized with a motion picture track. At least one of the audio tracks is a mixing master or a switching master. A mixing master is a track which includes MandE, but for the most part no dialog. A switching master is a track which includes MandE, together with dialog in a particular language. Other tracks on the disks are specific to respective languages and include material that is language specific. Where no language-specific material is required for a particular audio track, nothing is recorded so that there is no wasted xe2x80x9creal estate,xe2x80x9d as will be described below. Consider the case of a mixing master MandE track, and three language-specific audio tracks in English, Spanish and French. For a two-hour movie, the MandE track might have recorded close to two hours of audio. (Where there is no sound at all, there is no need to store any data, once again in order to avoid wasting any storage capacity.) The three language-specific tracks have dialog recorded in them, but no music and no effectsxe2x80x94and each of the three tracks his data recorded in it only where it is necessary for dialog. The user selects one of the three tracks, the French track, for example, if he wants to hear the French version of the movie. The mixing master audio track and the French audio track are the only ones which are read by the player, and he digital information recorded in the two tracks is mixed, so that the net result is a conventional soundtrack, in French. To play the Spanish version of the same movie, the user would simply select the Spanish-soundtrack instead of the French.
A switching master, on the other hand, would typically include dialog. Consider a motion picture which is originally shot with the actors speaking English. The switching master audio track would include the original motion picture soundtrack. To play the English version of the release, the switching master audio track would be played by itself from beginning to end. But suppose that it is desired to play the French version of the motion picture. In this case, the French audio track would include not only French dialog, but French dialog together with music and effects. All that is necessary to derive the French version of the motion picture is to play the switching master audio track most of the time, but to switch from it to the French audio trackxe2x80x94and to play the French audio track alonexe2x80x94where there is French dialog. The major difference between using mixing and switching masters is that the former is mixed with one of the language-specific tracks so that MandE can be (although does not necessarily have to be) recorded only on the master track, while in a switching system only one track is played at any given time so that MandE has to be recorded on the language-specific tracks. It is also possible to provide both schemes on the same disk, i.e., to provide both kinds of master tracks, with some of the language-specific tracks being used with the mixing master, and some being used with the switching master.
The disk includes within its lead-in section a series of codes which identify whether each audio track on the disk is a mixing master, a switching master, a track to be mixed with a mixing master, or a track to be switched with a switching master. There are a maximum of 16 audio tracks which may be provided. However, there are many more languages than this number. It is necessary to identify which languages are available on the disk so that the user can control his player to generate a soundtrack in the desired language. For this reason, the lead-in section of the disk identifies which languages are available on the disk. In the illustrative embodiment of the invention, the first audio track is an MandE track, a mixing master or a switching master. If there are a total of N audio tracks, where N is 16 or less, then there may be N-1 language-specific audio tracks. (There would be N-2 language-specific tracks if both mixing and switching masters are provided.) If the first track is a mixing master, then there can be at most N-1 language-specific versions since dialog is available only starting with the second track. (Theoretically, if the first track is a switching master and it contains dialog in the original language, then this track can be played alone from beginning to end and there are N language versions available.) If a player determines from an analysis of the lead-in section of the disk that the first audio track is a mixing master and the fourth audio track contains dialog in French, and it this fourth track that is to be mixed with the mixing master, then all that is required for generation of a French soundtrack is to mix the first and fourth soundtracks. This is not to say that there will always be data in these tracks. On the contrary, the underlying assumption of the invention is that the French-specific audio track will, more often than not, contain no data.
Information recorded on the software carrier is recorded in separately identifiable blocks. This is true for both video and all of the synchronized audio. Each block contains indicia of which audio tracks in the block represent a signal. Thus, a particular block may contain switching master information, as well as information in a language-specific track which is to be switched with the switching master. When the player determines at the start of the reading of a block that the block contains data in a language-specific track, it switches from play of the switching master to play of the language-specific track. All it takes is a single bit for each of the up to N tracks at the beginning of a block to allow the player to determine whether respective language-specific information is in the block being processed.
Other features of the invention will be described below. For example, a citizen of Spain, who purchases a player and optical disks in Spain, can be assumed to want to hear Spanish versions of a motion picture. Therefore, a player sold in Spain should xe2x80x9cdefaultxe2x80x9d to play of a Spanish audio track if one is available on the disk. Only if the default language is not available, or the user actually wants to hear dialog in a different language, should she be required to choose from among the available languages. How the data is stored on software carriers, and how it is accessed and played, will be discussed at length below.
The invention is disclosed in the context of an overall system which offers numerous advantageous features. The entire system is described although the ,appended claims are directed to specific features. The overall list of features which are of particular interest in the description below include:
Video standard and territorial lock out.
Play in multiple aspect ratios.
Play of multiple versions, e.g., PG-rated and R-rated, of the same motion picture from the same disk, with selective automatic parental disablement of R-rated play.
Encrypted authorization codes that prevent unauthorized publishers from producing playable disks.
Provision of multiple-language audio tracks and multiple-language subtitle tracks on a single disk, with the user specifying the language of choice.
Provision of multiple xe2x80x9cotherxe2x80x9d audio tracks, e.g., each containing some component of orchestral music, with the user choosing the desired mix.
Variable rate encoding of data blocks, and efficient use of bit capacity with track switching and/or mixing, to allow all of the above capabilities on a single carrier.